Phillip H. Kuo, MD, PhD, spoke about incorporating prostate-specific membrane antigen–PET imaging into multidisciplinary care for patients with metastatic castration-resistant prostate cancer.
Phillip H. Kuo, MD, PhD, professor of medical imaging, biomedical engineering, and medicine as well as member of the Graduate Faculty at The University of Arizona College of Medicine in Tucson, spoke with CancerNetwork® at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting about multidisciplinary care for patients with metastatic castration-resistant prostate cancer. He specifically focused on using prostate-specific membrane antigen (PSMA)–PET imaging, which was used in the the phase 3 VISION trial (NCT03511664) to identify patients with previously treated disease who were acceptable for randomization to 177Lu-PSMA-617 (Pluctivo) or standard of care treatment.1 The substudy aimed to determine if standardized uptake value (SUV) mean by 68Ga-PSMA-11 PET/CT imaging could be predictive of outcomes with 177Lu-PSMA-617, with results showing that the experimental therapy resulted in better overall survival vs the control arm consistently across groups.2
Prostate cancer care is already a very multidisciplinary space. The nuclear medicine component of it has already played big part for quite some time, not only from the diagnostic standpoint of, for example, the bone scans that have been around for decades, but even for palliative care. We had beta-emitting isotopes that many people may be familiar with like quadramet [Samarium (153Sm) lexidronam]. More recently, we had the first FDA-approved alpha-emitting therapy in radium [radium-223], which showed a 4-month improved survival in patients with bone metastases but no solid organ metastases. Now, the nuclear medicine team will be able to play an even bigger part in metastatic castrate-resistant prostate cancer.
This theragnostic paradigm shows the power of nuclear medicine that may be involved in patient selection with imaging, but also in the therapeutic arm with 177Lu-PSMA-617. In the VISION trial, they tried to get at least 4 cycles of therapy and then go to a maximum of 6 cycles if they showed a good response, importantly with tolerable adverse effects. What these results show are 2 things that might change practice. Routinely in practice, SUV mean is not reported out, so we may have to change our workflow to report it. Fortunately, there are artificial intelligence algorithms and software that are being rapidly developed that might allow us to do that on a routine basis as the standard of care so we can apply that SUV mean parameter to daily care to further personalize oncologic care. [For example, it may be evident that a certain] patient is going to do better than [having a 15.3-month overall survival as was demonstrated at the initial read-out of the VISION trial and may be at 21 months such as in those in the substudy within the highest standardized uptake value mean quartile]. Beyond just PSMA-PET scans, there are a lot of things that can factor into how well a patient is going to do [such as] their hemoglobin, the LDH [lactate dehydrogenase] values, and a lot of other things. We also have to take into account how many therapies they received and their bone marrow reserve. It’s always going to be a multidisciplinary decision with, of course, the patient at the center.